OMAP2/3: PM: push core PM code from linux-omap

This patch is to sync the core linux-omap PM code with mainline.  This
code has evolved and been used for a while the linux-omap tree, but
the attempt here is to finally get this into mainline.

Following this will be a series of patches from the 'PM branch' of the
linux-omap tree to add full PM hardware support from the linux-omap
tree.

Much of this PM core code was written by Jouni Hogander with
significant contributions from Paul Walmsley as well as many others
from Nokia, Texas Instruments and linux-omap community.

Signed-off-by: Jouni Hogander <jouni.hogander@nokia.com>
Cc: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>